Waters are presently purified for two main purposes:
xe2x80x9cAxe2x80x9d river waters are purified to become potable waters, and
xe2x80x9cBxe2x80x9d sewage waters are purified sufficiently to become acceptable for discharge into rivers.
There are many other cases, e.g. river waters needed to be purified to a degree to be used by a particular industry. All such various cases, too numerous to mention, are considered rather sub cases of the above general xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d categories. Effluents of industries which are not liable to biological purification are not subject to the proposed installations.
In cases xe2x80x9cAxe2x80x9d, as above, the purification of waters is done by employing physical and chemical methods using costly concrete structures, while in the cases xe2x80x9cBxe2x80x9d, as above, the purification of waters is also done using costly concrete structures but by employing biological methods in conjunction with physical-chemical methods.
The proposed installations introduce a considerable deviation from the above xe2x80x9cAxe2x80x9d and xe2x80x9cBxe2x80x9d methods. It aims to transform the purification of waters to predominately agricultural methods with the result to abolish the great majority of the costly concrete structures.
Plant roots supply the plants with plant nutrients which are of great variety but predominately phosphates and nitrates. Certainly the plants in addition to plant nutrients they absorb water and carbon dioxide. Therefore in the body of the herbivorous animals we shall find chemical combinations which were derived from plants plus oxygen and water. Now in the body of the flesh-eating animals, such as man, we shall find chemical combinations which had been derived from oxygen, water and from what was originally in the body of the herbivorous animals.
Water impurities from inhabited areas are generated mainly from human bodies (water-closets, sinks, baths etc.) with the result that sewage contains nitrogenous and phosphoric chemical combinations which originated from plant nutrients. Such impurities are broken down and consumed as their food by micro-organisms. It is proposed to create an environment whereby the growth of plants is assisted. The plants would be harvested and taken away from the system as fast as the impurities enter such a system.